bbarnettdreyfuss – Page 6

Share & Tell – Sp2011

Dave Kagan introduced the rules & procedure for Share ‘n Tell including the dreaded gong!

Participants at the Spring 2011 NCNAAPT Conference

Bree Barnett Dreyfuss – Amador Valley High School
Recently Bree used Energizer AA batteries in a physics lab only to find that several students were being shocked by them. It turns out that the plastic covering on the bottom terminal of the battery was not very well covered and the multi-stranded wire used in the experiment was poking underneath the covering and shorting out the battery. Duracell AA batteries have a better covered bottom terminal. Energizers can be fixed by putting a hole reinforce on the bottom terminal so that the gap is sealed. If you attend her workshop later in the day you can try shocking yourself as her students did.

Tom Rossing – Standford University
Tom demonstrated a noise maker to discuss resonance in open and closed air tubes, self-resonant tuning fork/choir chime made from extruded aluminum.

Jeff Jorgensen – Arroyo High School
Introduced his Case study Portfolio – a how-to about his “case study” activity. Case studies on a variety of topics are available on his website. You can also access his site by going to http://ahs.schoolloop.com and under “Directory,” then “Staff,” choose Jeff to access his webpage. Feel free to email him as well: jjorgensen@slzusd.org.

Don Rathjen – retired from the Exploratorium Teacher Institute & Foothill High School
Don demonstrated a simple ballistic pendulum (used to measure muzzle velocity) made Teacher Institute-style with a plastic bottle and string. It allows you to measure the muzzle velocity of a toy dart gun. Don’s activity write-up is available here.

Frank Cascarano – Foothill College
Frank shared an angular momentum demo using cordless drill, pvc pipe, drill bit, rotating table. When standing on a rotating platform the drill is run like a helicopter, that makes him rotate in the other direction to conserve angular momentum. Frank’s website is here and his email is FCPhysics@gmail.com.

Dean Baird – Rio Americano High School
You know the Power Balance bracelet? He analyzes the videos and shows that the bracelet does not in fact make you stronger, his YouTube lesson shows the fallacy. He first delved into the phenomenon in his blog entry “Power Balance Bracelet,” and is now working on a full lesson on it.

Dean also demonstrated a jelly baby wave machine using Dots candy rather than buying the expensive demo. Put two dots per side on a bamboo skewer and attach with duct tape. Dean discusses his wave machine in “Connecting the Dots” on his blog, “The Blog of Phyz.”

Clarence Blakken – Gunn High School (retired) and Vernier
Vernier is giving out awards; Clarence wanted to share the new probes from Vernier and his Weblabs available on his website. Also, Great America Physics Days are coming soon! Be sure to check out the Electronic Data Collecting center at the Great America Physics Day.

Tucker Hiatt – Branson/ Wonderfest/ Standford University
Tucker discussed grading strategies including using an error range as we do use in science. For example if they got a 35/45 +/- 3 points may help deal with complaints.

Dan Burns – Las Gatos High School
“A Discovery is an event that reveals your ignorance.” – Dan Burns

A light shown in an LED creates a voltage. A red LED shown into a green LED will not produce a voltage to get it to light. Red LEDs do not have enough energy to give to a green LED (that has a larger band width) but a blue LED can “power” a green LED. A UV LED does not light any color, despite the fact that they have a larger amount of energy. Resource: Center for Nanoscale System Institute for Physics Teachers, reference the “Phantasic Photon” lab for more details.

Veenu Shekhar – Silicon Valley Labs
Veenu helped to manufacture labs about LEDs & solar cells for high school students. Have a grant from the EPA and working on more to produce labs for electronic labs for middle and high school students.

Jeff Arrigotti – PASCO (thank PASCO for the donuts!)
Jeff will be giving away a car track for dynamics and collisions (full set up with springs, etc. and a second one with Physics kit). The car tracks can be attached to several different set ups for multiple experiments.

Gunjan Raizada Chakravarty “Dr. G” – “Sowing the Seed of Physics”
Dr. G has been doing Physics workshops for elementary kids in libraries – gave an example of an inquiry style activity that she does with children. More information is available on her website.

Bernard Cleyet – retired
Explored the conductivity of the hot glue to see if it was the cause of a faulty glue gun (as reported on a PTSOS listserve). Also ask people to respond to a quick questionnaire.

Paul Robinson – San Mateo High School
Lunch is not provided – we will be providing refund for funds collected.
National level (AAPT) update – national meetings need more attendees and possibly reduce number of meetings?
Mentioned his website, www.laserpablo.com and his lab manual is out of print – available online now

Keynote: Blinky Lights

By Don Rathjen and Paul Doherty (absent presenter Sebastian Martin) from the Exploratorium

A link to the powerpoint that accompanied this presentation will be linked soon.

“Blinky Lights” is a nickname for a small LED light by Inova called a MicroLight. The light has three settings: bright, dim and blinking. Pressing the light once sets it to bright which is on constantly; two clicks is dim and then three clicks is blinking. The dim setting is actually oscillating on a duty cycle that blinks it back and forth very fast. You can see this by setting it to dim and then waving the light in front of you. The “slow blink” is actually a 3Hz blink rate.

Using a Radio Shaq amplified speaker (~$15), Paul hooked it up to a solar cell and could audibly hear the change in the sound. He analyzed the sound using a free audio analysis software called Audacity and found that the light had 100 cycles/ second. The frequency was actually 97 Hz +/- 3%. Solar cells are attached to a mono mini 1/8” phone jack can be plugged into the speaker or an oscilloscope. The duty cycle is about 10% so that it blinks once every 1/100 hundredth’s of a second, a frequency of 100 Hz. It has recently been discovered that some new ones may be at 200 Hz on dim.

The human eye refreshes in such a way that one bright flash at least one microsecond long will cause the cones to fire for one tenth of a second. The amount of time that the cones continue to flash after depends on the brightness of the light. The memory of a retina is 1/10 of a second but the eye “forgets” 1/8 of a second later.

Blinky Lights can be used to determine the speed of motion of an object if the distance is known. You count dots (100 dots = 1 second). Cameras used have to have a longer exposure time (preferably on a tripod) in order to catch prolonged motion. Cameras can also be on “night setting” on cheaper cameras or even camera phones with the flash off. Either way the exposure time has to be increased; some actions will need only one second while some more artsy photos will need longer. A simple picture like the bike wheel below has a one second exposure time:

Blinky Bike Wheel — Paul demonstrates circular motion

Blinky Light Bat — Blinky Lights attached to a baseball bat

Paul demonstrated that the Blinky Lights can be attached to a baseball bat in three places: at the handle, near the head and at the sweet spot. When hung loosely from the handle and struck at the bottom, the baseball bat travels but the blinky light at the sweet spot reveals that the center of mass will travel in a parabolic shape. If struck at the center of mass it will translate to the side with rotation in the other direction. You can find the center of percussion by finding the place that allows the bat to fall straight down without rotation.

Blinky Lights can be attached to a long PVC pipe as well to explore vibration images, resonances, etc. Qualitative observations can be made about several objects without measurements. Blinky Lights can be helpful to show time lapse of specific types of motion.

Blinky Lights are very helpful to show freefall and the acceleration due to gravity by attaching a blinky light to a ball. Two blinky lights on opposite sides can be used to experiment with different pitches.

Blinky Free Fall — Blinky lights show Free Fall

Don explored how to update role of the old fashioned spark timer using blinky lights. Without measuring time precisely you can say the distance between each pair of dots is a “tic” and use it as a unit of time. By measuring the distance in between you can determine the distance per “tic.” Don showed how by cutting it up you can create a velocity to time graph with each unit of “tic.” This can be adapted with a blinky light on the same moving object. By counting blinks and using a measuring device such as a meter stick within the shot you can create the same type of graph.

Don also modeled how to show acceleration of a two speed shifting toy car as it shifts speed. Blinky Lights can be attached to a variety of cars in order to model different times of motion including constant velocity, acceleration, going over a hill, a “loop-de-loop,” etc.

A 2 Speed Shifter Car modeled with blinkies

Paul and Don also shared information about the Teacher Institute at the Exploratorium and several of their electronic sources listed below:

Paul Doherty’s webpage

The index page for his activities

The Blinky Light Snack from the Exploratorium’s Snackbook

Sebastian Martin’s home page

Sebastian’s Light Traces explorations

Don Rathjen’s activity index page

The Exploratorium main page

The Exploratorium teacher pages for educators

The Exloratorium free image repository database and video repository

Bree Barnett Dreyfuss’ qualitative Blinky Light Lab with student examples as well as pictures from years past on Flickr

Fall Mini-Conference Share n Tell

At every section meeting one of our most popular portions is the Share n Tell during which participants have five minutes to share a demo, idea, concept, book, problem, example, etc. Talkative participants must fear the dreaded gong at the end of five minutes. Below please find notes and relevant links from the special double session of Share n Tell from our Fall NCNAAPT Section Meeting and mini-conference:

Don Payne, Carondelet High School

A Piezo Electric popper (spark fed) has been adapted to drive a small toy car. A film canister is filled with either ethanol or Bonaca breath spray. By igniting the propellent the can be shot in one direction as the car moves in the other. Can be used for momentum collisions or projectile motion and potentially adapted for use with photogates. Black film cans with gray lids with a lid work the best and a Nerf ball was added tot the launching end of the can for safety for projectiles. Nicknamed as the “Bonaca Cannon” at the conference, the car is made from a small wood base, Pisco (?) aluminum axle wheels and electric leads for ignition.

: Piezo Electric Car

Paul Robinson, San Mateo High School

Horace (Rog) Lucidio taught in Pittsburgh and then Fresno. He has since retired and published a book called “Educational Genocide” just recently out. It is available from Amazon or AbeBooks, and comes highly recommended. Read the press release here.

Bernard C, retired

Bernard demonstrated a “Poisson’s Spot” demonstration, misnamed because you shouldn’t get light behind a barrier which in this case is a 4” “ball bearing” used to block the microwave signal AC Amplifier (with sound signal so it doesn’t need to be in the dark). Can be shown to block specific zones so that it acts as a positive lens and increase the size of the signal using Fresnel Zoning.

Bree Barnett Dreyfuss, Amador Valley High School

Bree shared a “Center of Mass” Project that students do while studying Torque and Center of Mass. The project is adjusted for a variety of levels including freshmen in Conceptual Physics. There is a website with details and YouTube video that explains the details of the project to students. Sophomores to Seniors in regular Physics have to bring in a balanced object, either a mobile, 3D sculpture or flat oddly shaped object. The flat character/ geographic region is the most popular and allows for the most creativity. Students have also used powerpoint, made videos with classmates and even hand drawn animations in order to demonstrate their understanding of Center of Mass. For younger freshmen, the project is restricted to create a flat creative object and bring it in to class. Then together, they learn how to find the center of mass of their object using a plumb bob.

Cailin Creighton, iFly educational leader

Cailin is in charge of the education program at the Union City iFly facility and has offered affordable field trips for teachers. She shared models and instructions of a handmade vertical wind tunnel out of a cereal box and plastic bottle. Instructions to come soon. Cailin used a Kellog’s 18 oz cereal box and an Archer Farms water bottle – plastic not glass to create the frame of the wind tunnel. A 80 mm commuter fan hooked up to a 9V battery runs the fan and allows a light object like tissue paper to fly. This model models the Hollywood (single side tunnel) while the local Union City one has two sides of fans feeding in to the tunnel. Turning vanes are not necessary for the cereal box model due to the simplicity of the design. It was suggested to try adding dry ice to simulate a tornado. 1” Styrofoam balls cut in half will fly, while a whole ball will not fly which is interesting because they have the same surface area but a different weight. Cailin’s contact information is Cailin@iflysfbay.com.

Paul Doherty, Exploratorium

Paul shared the classic Reaction Time experiment adapted to work for a baseball bat that is marked with reaction times. Average human reaction is 0.16 s, volunteer Pablo got 0.22s, then 0.2 s which is consistent with experiments as students improve with time.

Putting a stiff card at the top of the baseball bat acts as an amplifier. You can strike the bat at different locations and hear an amplified thud. The sound will decrease as you reach the “sweet spot” which is a vibrational node. This is why hitting a home run on the sweet spot feels better than hitting off the spot.

Don Rathjen, Exploratorium

A Fan cart is helpful in teaching Newton’s Third Law by moving the fan and sail positions to show that when both are on the same cart it will not move. Don has a fabulous design that is very low friction. Don also added a waterbottle that was cut in half with the “sport top” that pops up that can be used to create a consistent drip timer. This can be added to the fan cart to work as a drip timer for motion to model motion.

Lee Trampleasure, Carondelet High School

Lee (who had lost his voice) shared a humorous PowerPoint on Newtons three laws (Newton, North Carolina, that is) with single picture explanations of each of Newton’s Three Laws:

1^st law: 35 mph Speed Limit sign
2^nd Law: “no left turn” sign
3^rd Law: “no parking” sign

Pauline Seales

Pauline described a demo in which she asks a “strong” student to bend a nail with their bare hands, which they can’t do. She then asks a “small” student to bend it and hands them two pieces of metal pipe that are inserted on each end of the nail (increasing the lever arm distance) and they are able to bend it easily.

Pauline also modeled using a pre-cut mop handle attached with a PVC pipe to show how balanced Torques does not mean balanced forces. Students often don’t believe her and have to weigh the broom head (heavier) and handle (lighter) themselves because they don’t believe her.

Pauline with mop — Pauline with precut mop

Dean Baird, Rio Americano High School

Showed Simple Harmonica Motion:

Dean also discussed a large mural of white light reflected on an equilateral triangle outside his room with almost the right angles. He showed a video of a Newton’s Cradle that does not behave normally as discussed in his blogpost.

Paul Doherty added that the Exploratorium recently created a large Newton’s “ridable” Cradle with 1 meter diameter Lexican balls. Paul also told us about the Exploratorium’s After Dark adult only program that goes from 6-9pm, on the first Thursday of every month.

Rob Benn, American High School

Using video in the classroom using iMovie, iPods, iTouches, etc. in order to model Bridges, motion at Great America, etc. Can also be used with high speed cameras. VideoPoint is additional software that you can use. The FH100 Casio will do 1000 frames/ second but is $300. Students participate in Knieval Physics which makes for interesting videos. Due to the wealth of information available from Rob, he was encourage to do a workshop next time.

Dean Baird, Rio Americano High School

Dean showed an additional short film of a Newton’s Cradle in which the balls appear to fly apart. After showing a hint video we were able to see the answer, all videos available on his blogpost.

J Robert Dobbson

Dobbson shared a Gaussian Cannon that can be made rather than bought with ½” steel ball bearings and neodymium magnets on a plastic ruler. Having an assistant pull the last ball, last two balls and last three balls off the end you can learn that the approximate magnetic strength changes with proximity to the neodymium magnet. Allowing the first ball to fall down a small incline the loss of potential energy becomes kinetic energy. The ball also gains energy as it is attracted to the magnet and as the energy grows the last ball flies off at a larger velocity.

Dobbson also shared a coil of magnetic wired that he had to modify so that it appropriately showed the magnetic field inside the coil without being affected by the lights. He coiled 10 cm, made a Uturn in the coil for 20 cm, used another Uturn and then another 10 cm.

Rodger Moorehouse, Pomona

Rodger discussed the history of different temperature scales and their origins.

Bree Barnett Dreyfuss, Amador Valley High School

Bree shared a variation of the Blinky Light activity from her website as well as an online game about Torque called Levers.

Paul Robinson, San Mateo High School

Paul shared the ramp he designed which is very repeatable and consistent. He was unable to show his baseball videos but they are available on his website.

Spring NCNAAPT Section Meeting

Thanks to all that came and made the Spring NCNAAPT Section Meeting a success! Below please find all the notes taken at today’s conference with available links and contact information. If you see a mistake or would like something added/ changed please contact the Secretary, Bree Barnett Dreyfuss.

If you need proof of your attendance to today’s conference, you can download a Certificate of Attendance to print. Any questions can be sent to the Secretary.

Afternoon Workshops

Workshops in Room 307

Cailin Creighton, iFly: Cailin explained the format of educational programs available at iFly Indoor Skydiving in Union City, CA. There are several topics available for lectures, classroom examples as well as experiments at the facility. The educational program includes a tour of the wind tunnel, a lecture tailored for your class and one minute flights for students. Information about the program is available here. Any material developed by teachers relevant to the iFly experience can be sent to Cailin and contributed to a teacher resource page. (cailin@iflysfbay.com) Promo Code: “EDUCATION” 20% off first time flyer “earn your wings,” “spread your wings,” and “take flight” programs.

Scott Perry, Wind Energy: A Sustainable Future?: Scott discussed the possibilities for sustainable energy and some of the difficulties with such a discussion. One hurdle that teachers can appreciate is that each country or business entity deals in different units (barrels of oil, BTUs, kWh, etc.). Scott suggested that everyone read David McKay’s book “Sustainable Energy Without the Hot Air;” it is a free publication that discusses different sustainable energy options. Jared Diamond’s book “Collapse” was also recommended which discusses several populations use and overuse of energy sources.. The United States (~5% of the world’s population) uses ~20% of the energy used in the entire world. Some companies are looking at larger wind farms along the coasts of the United States; it is a goal that 20% of the United States Electric Energy Production by 2030 is wind energy.

Byron Philhour, Lunar Landing Project: Students produce numerical simulations of an Apollo-style launch using kinematics & drag equations. Students are supplied with the mass, and the thrust in conjunction with a drag atmospheric model to create this information. This project also requires students to work with angular momentum, energy, etc. to prepare for the Advanced Placement exam. The Lunar Lander Project is a long challenging assignment meant to challenge AP level students.

Bernard Cleyet, Not the Usual Coupled Oscillators: Bernard discussed various experiments using coupled oscillators and their decay.

Kevin McLin, Using Global Telescope Networks for Research & Science Education: Kevin discussed various programs that use telescope networks and allow students in high school, middle school and even elementary school to work with data from these networks.

Bree Barnett Dreyfuss, Using Class Facebook Fan Pages: Facebook is a free online social networking site that allows people to share information, pictures, etc. A “fan page” can be created for a classroom that allows students to communicate with each other and the teacher in a different format. Instructions were given on how to create the page, as well as warnings and suggestions. You can visit Bree’s fan page or obtain workshop information on her website under “Professional Development.”